189 results about "Cold shield" patented technology

The invention relates to a conduction-cooled superconducting magnet Dewar with easy loading-unloading, comprising a Dewar cylinder. The conduction-cooled superconducting magnet Dewar is characterized in that the Dewar cylinder is a hollow annular cylinder, the middle of the annular cylinder is provided with a room temperature hole, an annular copper cold shield is arranged in the Dewar cylinder, a refrigerator and a superconducting magnet are arranged in the copper cold shield, a vacuum pumping port is arranged on the Dewar cylinder, a measuring device is arranged on an upper cover of the Dewar cylinder and the Dewar cylinder is in a vacuum state. Compared with the prior Dewar container, the conduction-cooled superconducting magnet Dewar is simpler, has small conduction heat leakage, and has the advantages of easy installation and disassembly; the refrigerator is used for conducting and cooling without a low temperature liquid (such as liquid helium and so on) cooling system; because of simple and safe system, a first-level cold junction of the refrigerator is operated under a temperature of 77K, thereby realizing heat sink of the copper cold shield, an electric lead and a support device; the first-level cold junction of the refrigerator adopts soft connection, thereby reducing temperature increment of the magnet due to vibration of the refrigerator; and the conduction-cooled superconducting magnet Dewar has the advantages of easy operation of manufacture, processing and installation, and is applicable to scale production.

Multiple detectors arranged in a ring within a specimen chamber provide a large solid angle of collection. The detectors preferably include a shutter and a cold shield that reduce ice formation on the detector. By providing detectors surrounding the sample, a large solid angle is provided for improved detection and x-rays are detected regardless of the direction of sample tilt.

A continuous zoom lens arrangement can image MWIR and LWIR spectral bands to a common image plane. Such an exemplary optical system comprises eight infrared imaging lenses that all transmit over the wavelengths 3.5-11.0 microns and form a collocated image plane for the MWIR and LWIR spectral bands. The lens has six stationary lenses, and two lenses that move in arm axial fashion. A cold stop inside the dewar can act as the aperture stop of the system and control the stray light from reaching the FPA. The pupil is reimaged from the cold stop to near the first lens of the system to minimize the size of the lens. The optic is designed to operate at an f/number of 3.0 and provides a focal length range from 38 mm to 130 mm for a 640×480 element focal plane array with 20 micron square pixels. This has an equivalent image plane diameter of 16 mm. Such an optical system can work with a cold shield height of about 29.46 mm. The range in focal length result in an overall zoom change of 3.42×.

The invention provides a high temperature superconducting magnetic system protected by high heat capacity materials, wherein, a high temperature superconducting magnet (12) is arranged in a low temperature container (6); the periphery of the high temperature superconducting magnet (12) is coated with high heat capacity cold accumulation materials (17); a refrigerator (1) is installed in a vacuum container (2), and a primary cold head of the refrigerator (1) is connected with a cold shield (5) of the vacuum container (2) through a first heat pipe (3); a secondary cold head of the refrigerator (1) is connected with a low temperature container (6) through a second heat pipe (8); a first and a second cold conduction copper rods (23, 24) which are at the lower end of the second heat pipe (8) are connected with the high temperature superconducting magnet (12) through a cold conduction plate (15); a Y-Ba-Cu-O high temperature superconducting block (13) which is installed in external symmetry on the low temperature container (6) interacts with a permanent magnetic block (14) which is on the inner wall of the vacuum container (2), thus suspending the low temperature container (6); and the temperature signal of the high temperature superconducting magnet (12) detected by a temperature probe (18) is used for controlling the startup and shutdown of the refrigerator (1).

The invention discloses a high-field superconducting magnet system with wide separation gaps. Superconducting coils of the system comprise a low-temperature superconducting coil (16) and a high-temperature superconducting coil (17). The superconducting coils are connected with a cold shield (3) and a flange (2) of a low-temperature container through a support pull rod (8), and are supported in the low-temperature container integrally. A thermoswitch (7) is connected with a primary cold head and a secondary cold head of a refrigerating machine (1), and the secondary cold head is connected with magnet-reinforcing support flanges (10) arranged at two ends of the low-temperature and high-temperature superconducting coils through a cold-guiding belt (5). The superconducting magnet system is provided with a horizontal room-temperature hole (12) and a vertical room-temperature hole (15); an outer cold shield (11) of the horizontal room-temperature hole is used for preventing heat radiation of the horizontal room-temperature hole (12) to the superconducting coils. A separation support frame (9) separates the low-temperature superconducting coil (16) and the high-temperature superconducting coil (17) into two parts, so when the superconducting magnets are integrated into a whole, a two-dimensional room-temperature space is contained in the integrated superconducting magnets.

The invention discloses a poly-lens profound hypothermia infrared detector pipe casing structure packaged in a Dewar. The poly-lens profound hypothermia infrared detector pipe casing structure is applicable to the packaging technology of a profound hypothermia pipe casing arranged in an infrared focal plane detector Dewar and provided with a plurality of cold optical elements. The poly-lens profound hypothermia infrared detector pipe casing structure comprises a detector chip, an electrode lead wire circuit substrate, a plurality of lenses, an optical filter, a supporting pipe casing, a press ring type cold shield, a chip, a lead wire silicon-aluminum wire and the like. The poly-lens profound hypothermia infrared detector pipe casing structure achieves poly-lens profound hypothermia pipe casing high-accuracy packaging through special measures and structural modes such as laser positioning drilling, the nested press ring type cold shield, the special alloy integrated supporting pipe casing and lateral surface fine tuning aligning, can effectively meet hypothermia infrared optical accuracy requirements, reduce the background in a chip view field, stray light and heat radiation of the whole Dewar and effectively remove low temperature deformation stress of the ceramic sintered pipe casing on the detector chip, and is applicable to other radiation cooling, thermoelectric refrigerating and the like.

The invention discloses a vertical container used for storing low-temperature liquid. The vertical container comprises a shell provided with a seal cavity, an inner container mounted in the cavity and used for storing the low-temperature liquid and a cold source container used for storing liquid nitrogen; the outer side of the inner container is coated with a liquid nitrogen cold shield, a liquid nitrogen cooling pipe is arranged on the liquid nitrogen cold shield, and the liquid nitrogen cooling pipe and the cold source container are communicated to form a liquid nitrogen circulation loop; and the vertical container mainly adopts a heat insulation manner combining vacuum multi-layer heat insulation with the liquid nitrogen cold shield to reflect the excellent heat insulation performance. An inner container used for storing liquid nitrogen media is arranged in the vertical container, the independent liquid nitrogen cold source container and the independent liquid nitrogen cold shield are arranged, through dissipation of liquid nitrogen in the cold source container, the heat wall temperature of the liquid nitrogen container is reduced to 77 K from 300 K, the radiant heat flux is reduced to 1/150 to 1/200 of the original flux, and therefore the aim of greatly reducing the daily evaporation rate loss of the container is achieved.

The invention discloses an extra-static liquid helium thermostat and relates to a liquid helium thermostat. The thermostat comprises a shell, an inner container, a bottle neck, a gas exhaust and inflation pipe, a helium outlet pipe and a cold shield, wherein, the inner container is arranged inside the shell; one end of the bottle neck extends to the bottom of the inner container from the top of the inner container and is sealed and connected with the bottom of the inner container; the other end of the bottle neck is communicated with the outer part of the shell by the top of the shell; the inside of the bottle neck is communicated with the outer part of the shell by the gas exhaust and inflation pipe; the cold shield is arranged between the inner container and the shell and covers the inner container; the helium outlet pipe is wound around the cold shield; the two ends of the helium outlet pipe communicate the inside of the inner container with the outside of the shell; vacuum is formed between the outside of the inner container and the inner surface of the shell; an auxiliary helium outlet pipe can be added and wound on the bottle neck; the two ends of the auxiliary helium outlet pipe can communicate the inside of the inner container with the outside of the shell; and the bottle neck can be made of a corrugated pipe. The bottle neck extends to the bottom from the top of the inner container and is sealed and connected with the bottom, so as to obtain a lower temperature cavity body separated from the liquid helium, and avoid the shock caused by the collision of the boiling of the liquid helium with the experimental facilities in the bottle neck. Two helium outlet pipes are utilized to cool the cold shield and the bottle neck, so as to reduce helium evaporativity.

The invention discloses a system of treatment by deep cooling with temperature controlling based on natural circulation. The system is composed of liquid nitrogen tank, filling port, perfusion valve, perfusion tube, heat insulating layer, cold shield, treatment room for deep cooling, internal coil, external coil, pressure transducer of internal-coil entry, temperature transducer of internal-coil entry, fan, nitrogen cylinder, reducing valve, injection control valve, injection tube, pressure transducer of external-coil entry, temperature transducer of external-coil entry, temperature transducer in treatment room for deep cooling, reflux control valve, reflux tube, data acquisition of computer and control system. The system depends on pressure-difference resulting from different consistency of liquid nitrogen and gas nitrogen to impel coolant of liquid nitrogen for circular flowing. Adjusting of coefficient of heat transfer on the surface of work is realized conveniently by controlling flux of circulate liquid nitrogen and rotate speed of fan. The system has much strongpoint including saving circulate power and consumption of liquid nitrogen, easy to control cooling speed of treatment by deep cooling and treatment temperature etc.

A condensation trapping apparatus used for pumping and cooling rarefied air by liquid nitrogen relates to a trapping apparatus. The invention solves the problems of high cost, poor operability and being hard to realize needed cooling temperature existed in the existing rarefied air condensation trapping apparatus. A cold shield assembly (26) is arranged in an outer barrel (21); a liquid nitrogen chamber (25) is arranged at the bottom part of the cold shield assembly (26); a liquid air collecting disk (28) is arranged in the cold shield assembly (26) and is arranged below the liquid nitrogen chamber (25); a liquid air collecting Dewar (17) is arranged in a bracket assembly (27) and is communicated with the liquid air collecting disk (28) above the liquid air collecting Dewar (17); one end of a nitrogen extraction tube (5) penetrates a heat preservation cover (26-1) of the cold shield assembly (26) and is communicated with the upper end of the liquid nitrogen chamber (25); a liquid nitrogen conveying pipe assembly (13) is arranged on the cold shield assembly (26). The trapping apparatus of the invention has the advantages of low cost, high operability and simple operation; besides, the trapping apparatus can provide a cold source with low temperature of 55 K and even lower temperature and can effectively realize to trap the air over 2000Pa.

A cold shield of a cryogenic camera. The cold shield reflects external thermal radiation away from the cryogenic camera, so as to shield the cryogenic camera in a cryogenic temperature such that no internal thermal radiation will be generated. The cryogenic camera has a lens assembly and a focal plane array. The cold shield has an upper cold shield member for holding the lens assembly and a lower cold shield member for holding the focal plane array. The upper cold shield member fits over the lower cold shield member by contact friction, such that limited translation and rotation of the lower cold shield member relative to the upper cold shield member are allowable. Therefore, the cold shield allows a fine adjustment for aligning the lens assembly to the focal plane array.

An infrared telescope utilizes two mirrors in an off-axis, eccentric-pupil, re-imaging configuration. To improve the image quality of traditional two mirror telescopes, the reflective surfaces of both the primary and secondary mirrors are ellipsoidal. The ellipsoidal surface of the primary mirror has a greater eccentricity than the ellipsoidal surface of the secondary mirror. The infrared light entering through the eccentric pupil strikes the ellipsoidal reflective surface of the primary mirror. The light is reflected from the primary mirror to the ellipsoidal reflective surface of the secondary mirror. An intermediate image of the object being viewed is formed between the primary and secondary mirrors. The light is reflected from the secondary mirror to an image plane. An aperture stop is located between the secondary mirror and the image plane. The image plane is typically located within a cold shield, to reduce the likelihood that stray light will reach the image plane.

The invention discloses an infrared focal plane detector component. The infrared focal plane detector component comprises imaging optical parts, a cold shield and a dewar, wherein the imaging optical parts comprise an objective lens and a cold stop which are integrated in the interior of the dewar; the objective lens is arranged on the window of the dewar or bonded with the cold shield; the cold stop is arranged on the cold shield, and the cold shield and the window seat of the dewar are the support pieces of the imaging optical parts. The infrared focal plane detector component solves the problems of the low temperature, the miniaturization and the athermalization of an infrared optical system in the correlation technique, the infrared imaging optical parts are integrated in the detector dewar component and made to be in a constant low temperature environment, therefore the self-emitted radiation of the optical system can be effectively controlled, the adaptive capacity to environmental temperature variations is greatly improved, and the optical system is significantly superior to a conventional imaging system in volume and weight.

The invention discloses a helium cooling magnetic resonance superconducting magnet which comprises a vacuum vessel, an accommodating cavity used for arranging a cryogenic vessel is formed inside the vacuum vessel, and a cold shield which is used for reducing radiation heat leakage of room temperature to the cryogenic vessel is further arranged in the accommodating cavity; a superconducting coil is arranged in the cryogenic vessel; a refrigerating machine is fixed on the vacuum vessel; a first stage cold head of the refrigerating machine is connected with the cold shield, a second stage cold head of the refrigerating machine is located in the cryogenic vessel, the helium cooling magnetic resonance superconducting magnet further comprises a helium gas pipe which is used for filling gaseous helium into the cryogenic vessel, the helium gas pipe comprises a stretching end which stretches out of the vacuum vessel, and a sealing ball valve which is used for preventing gaseous helium leaking when the helium cooling magnetic resonance superconducting magnet operates or the superconducting coil is invalid. The gaseous helium in the cryogenic vessel is specifically gaseous helium with 1-10 atmospheric pressure in room temperature. According to the helium cooling magnetic resonance superconducting magnet, the helium gas utilization ratio can be improved, and the maintenance process of the superconducting magnet can be simplified.

It is provided an optical system for changing a spectral range of a cryogenically cooled detector. The optical system allows selective spectral transfer of radiation, and provides a reflecting field of view at an undesired range directed towards cold surfaces. A removable spectral filter having a high transmittance at a first spectral range and a low transmittance at a second spectral range is disposed outside a cold shield. A reflective surface faces the detecting device and provides the detector a reflecting field of view at the second spectral range directed towards the cold shield, and a blackened cold skirt thereof. Alternatively, a dichroic mirror is disposed inside the cold shield and has a high reflectance at a first spectral range and a high transmittance at a second range. The detecting device includes a first arm and a second arm of the cold shield to accommodate respective optical channels. A removable selective mirror having a high reflectance at the first spectral range is disposed outside the cold shield. A reflecting field of view at the undesired spectral range directed towards a blackened surface of the cold shield or a thermo-electric cooler is provided.

The invention discloses a low-temperature propellant storage tank with a pressure control device. The low-temperature propellant storage tank comprises a low-temperature propellant storage tank body,a low-temperature circulation pump, a throttling valve, an expansion machine, a double-pipe heat exchanger, an exhaust cooling coil and an exhaust valve. In order to improve the heat exchange efficiency of the heat exchanger, the reverse-flow double-pipe heat exchanger is adopted, and more cooling capacity can be generated. Meanwhile, fluid passing through the throttling valve absorbs heat and becomes saturated gas or superheated gas which is expanded and cooled through the expansion machine after being discharged out of the tank body, the low-temperature gas forms a cold shield through the cooling coil wound in an insulation layer outside the tank body, external leakage is reduced to the greatest extent, and the exhaust cooling capacity is fully used. The low-temperature propellant storage tank is simple in structure and high in heat exchange efficiency, the cooling capacity is fully used, the tank body pressure is effectively controlled, and effective guarantee is provided for long-term storage of a low-temperature propellant and the tank body pressure.

The invention provides a long wave infrared three-view-field optical system. The optical system is sequentially composed of a front fixing set, a zoom set, a rear fixing set, an optical flat, a first reflecting mirror, a second reflecting mirror and a secondary image forming set from object space to image space. High order aspheric surfaces are adopted in a second surface of a lens of the front fixing set, a second surface of a first lens in the rear fixing set and a first surface of a second lens in the secondary image forming set. The working wave band of the optical system ranges from 7.7 micrometers to 9.5 micrometers, F # is 3, view fields are respectively 0.96 degree * 0.72 degree, 6 degrees * 4.5 degrees and 27 degrees * 21 degrees. The zoom set is moved, the optical flat is inserted, then, the large view field, the middle view field and the small view field can be achieved, consistency of optical axes of the three view fields is good; the zoom ratio can reach 28 times to the maximum, and image forming quality is good; the maximum stroke of the zoom set is smaller than 100mm, and 100% cold shield efficiency is achieved; an optical path is designed to be folded in a U type, and then the optical system is small in size, compact in structure and easy to adjust, and can be massively produced.

The invention discloses an ultralow-temperature and ultralow-vibration friction testing device, which comprises a helium liquefying mechanism, a friction mechanism and a storage tank, wherein the helium liquefying mechanism comprises a first vacuum hood and a first cold shield arranged in the first vacuum hood; a refrigerator penetrates through the first vacuum hood; a first-level heat exchanger and a second-level heat exchanger connected with a liquid conveying pipe are arranged on the refrigerator; the first-level heat exchanger and the second-level heat exchanger are positioned in the firstcold shield; the friction mechanism comprises a second vacuum hood, a second cold shield and an insulating bracket; the second cold shield and the insulating bracket are arranged in the second vacuumhood; the second vacuum hood is connected below the first vacuum hood; a liquid helium cavity is formed in the second cold shield; an exit of the liquid conveying pipe is formed in the liquid heliumcavity; an upper sample support is arranged on the outer bottom wall of the second cold shield; a movable displacement platform is arranged on the insulating bracket; a lower sample support is arranged on the displacement platform; the upper sample support and the lower sample support face each other up and down; the storage tank is connected with the first-level heat exchanger through a gas supplementing pipe and connected with the liquid helium cavity through a gas return pipe. According to the invention, a friction test of a sample can be realized in an environment with ultrahigh vacuum degree and ultralow temperature.

The invention discloses a low-temperature superconducting magnet which comprises a Dewar type container filled with liquid helium, a superconducting winding located in the Dewar type container, and a magnetic material-containing refrigerating machine partly located in the Dewar type container. The Dewar type container comprises an inner shell body, an outer shell body arranged outside the inner shell body, and a cold shield placed between the inner shell body and the outer shell body. The refrigerating machine is partly arranged between the outer shell body and the inner shell body and also comprises a magnetic shielding cover located around a magnetic material motion area in the refrigerating machine. The magnetic shielding cover is provided with at least two layers of shielding bodies with a gap between. According to the low-temperature superconducting magnet, the interference of the magnetic field of the magnetic material in the refrigerating machine on the magnetic field of the superconducting magnet can be effectively reduced.

The invention discloses a performance testing system for a quartz crystal microbalance (QCM). The performance testing system comprises a vacuum pumping system, a re-pressing system, a measurement control system and a vacuum chamber, wherein a cold shield is arranged in the vacuum chamber; the bottom of the cold shield is matched with a wafer testing device and a QCM probe testing device, and is used for supporting the wafer testing device and the balance probe testing device and providing two heat conductors to be arranged on the cold shield; the vacuum chamber is in vacuum connection with the vacuum pumping system and the re-pressing system; the vacuum pumping system is used for creating a vacuum environment needed by testing for the vacuum chamber; and the testing device is electrically connected with the measurement control system to measure temperatures and frequencies. In the testing system, a clean oil-free vacuum environment is provided, so that the frequency change of the QCM caused by pollution is avoided; and the performance testing system can be used for testing multiple performances of the QCM and a key component of the QCM, i.e., a wafer, and can be used for performing high-temperature aging on an applied balance, and the reliability is enhanced.

A detachable mechanism used for installing a low-temperature superconducting magnet refrigerator comprises a connection flange connected with the refrigerator. The connection flange is connected with a supporting flange through a corrugated pipe, a primary cooling pipe is connected with the supporting flange and a cold shield flange respectively, the upper end of a secondary cooling pipe is connected with the lower portion of the cold shield flange, and the lower end of the secondary cooling pipe is communicated with the inside of a helium tank. The refrigerator and components of the refrigerator can be conveniently mounted and dismounted through commonly-used sealing rings and bolts, and meanwhile a sealed space environment of the components can not be damaged. The refrigerator still can effectively play a refrigeration role through the corrugated pipe, the cold shield flange, the cooling pipes and other parts. The detachable mechanism is simple and compact in structure, simple in manufacturing technology, low in cost, good in interchangeability, low in maintenance cost, long in service life, good in universality, and capable of being modularized.